We investigate ATM traffic management and congestion control issues
related to satellite systems that include traffic management schemes to maximize
efficiency and fairness while minimizing delay and convergence time.
ACTS T1 VSAT Earth Terminal equipment.
Recent work has addressed optimization of performance of TCP/IP over satellite ATM
networks and switch algorithms. Of particular interest has been the work that is funded
by NASA and performed by Dr. Raj Jain and his colleagues at Ohio State
University regarding segment-by-segment congestion control known as "virtual source/virtual
destination" (VS/VD). This control scheme is advantageous to long delay links as - in
the limit - each segment may be independently controlled. Additional work is being
performed regarding Internet protocols for ATM over satellite including TCP (Transmission
Control Protocol) over UBR (Unavailable Bit Rate) and TCP over ABR (Available Bit Rate).
The key parameters being studied are the system performance with limited buffers, and
buffer requirements for zero loss. Various algorithms are also under investigation such as
early packet discard, fast retransmit recovery and fair buffer allocation.
